Interstellar Comet

13 Sep 2019

At http://spaceweather.com (September 12th, 2019) ... another interstellar visitor is passing through the solar system it has been suggested. This time it is definitely a comet we are told - although it is very faint and the coma is by no means prominent. Comet Borisov (named aafter the person that first spotted it, hailing from the Ukraine), is approaching the inner solar system from beyond the orbit of Mars. It has what is called a hyperbolic orbit with an eccentricity greater than 3.5. This implies the comet is unbound to the Sun. It is also moving at 68,700 mph - too fast for the Sun's gravity to capture. It is therefore expected to continue right through the solar system and out the other side. The interesting bit will be inter action with the solar wind. Will it respond and brighten up or will the Sun be quiet and it will have come and gone without any fireworks.

A Swedish sky watcher took the image below ...

   ... a double rainbow. It was also a sunset rainbow in that the Sun was low on the horizon. It is caused by sunlight being reflected twice, inside raindrops.